SuperSocket is a light weight, cross platform and extensible socket application framework. You can use it to build a server side socket application (like FTP server, SMTP/POP3/IMAP4 server, SIP server, SNMP server, etc) easily without thinking
about how to use socket, how to maintain the socket connections and how socket works(synchronize/asynchronize).

It is a pure C# project which is designed to be extended, so it is easy to be integrated to your existing system. If your systems (like forum/CRM/MIS/HRM/ERP) are developed in .NET language, you must be able to use
SuperSocket to build your socket application as a part of your current system perfectly.

I know there are two famous NIO open source frameworks named "MINA" and
"Netty" in Java World which are used widely by developers. If you want to look for a .NET portion of MINA or Netty, I suggest you try
SuperSocket, although SuperSocket is not strong like MINA and Netty but it is very simple and you can use it easily.

The source code of SuperSocket also include some service implementation samples which you can follow.

Very easy to use. You can create a robust socket server only by several classes

Support Sync and Async communication modes. You can change your socket server running mode by only changing configuration wihtout any code changes

Support custom protocol, no matter your protocol is a command line protocol or a binary one. Another open source project
SuperWebSocketis built upon
SuperSocket and take advantage of this custom protocol feature of it.

Support SSL/TLS encryption automatically

Support multiple socket server instances. You can define many socket servers on different ports in configuration,
SuperSocket can run those servers in the same application/service

SuperSocket can run as console application and windows service. It provide a bat file to install
SuperSocket as a windows service.

Flexible logging strategy which can log most of socket activities

Also support UDP socket

Support IPv6

Support Windows Azure

Support running in Unix system (by Mono 2.10 or above version)

Built-in socket policy server for Flash and Silverlight clients which you can use directly